This description relates to strand lubrication.
To make it easier to pull a strand or multiple strands (e.g., an insulated electrical wire) through a conduit, the strand is often lubricated. One person typically applies the lubricant, for example, soap, to the strand by hand as one or more other people (depending on the diameter and weight of the strand) withdraw the strand from a coil or other supply and feed it into the conduit. One or more people at the other end of the conduit pull on the strand while it is being lubricated and fed.
The end of the conduit typically has an external thread. After the wire is pulled through the conduit, a standard cylindrical bushing is screwed onto the end of the conduit to protect the wire from damage that might otherwise be caused by the sometimes-rough edge at the end of the conduit.
Various devices have been proposed to simplify the process of lubricating the strand while it is being pulled.